Safety and Tolerability of Short-Term Ashwagandha Supplementation in Resistance-Trained Adults: A Biomarker Analysis

BACKGROUND: Ashwagandha (Withania somnifera; ASH) is widely used as a dietary supplement among physically active individuals; however, limited data exist regarding its short-term effects on clinical blood biomarkers and organ function. Evaluating the safety profile of ASH supplementation is essential to support its responsible use in athletic populations.METHODS: Twenty-three resistance-trained adults (9 males and 14 females) participated in a randomized, double-blind, crossover study examining the short-term safety of ASH supplementation. Participants completed three 7-day conditions in a counterbalanced order: low-dose ASH (LDA; 4 mg/kg/day), high-dose ASH (HDA; 14 mg/kg/day), and placebo (PL), separated by 7-day washout periods. Following overnight fasting, venous blood samples were collected after each condition and analyzed for hematological, hepatic, renal, and metabolic biomarkers. Data were analyzed using two-way repeated-measures ANOVA with Fisher’s LSD post hoc tests (p ≤ 0.05).RESULTS: Participants completed fasting blood assessments at CON and following each supplementation condition. No significant treatment effects were observed for lipid profile variables, including LDL, HDL, VLDL, total cholesterol, and triglycerides (all p > 0.05). Similarly, fasting glucose concentrations remained unchanged across conditions (p > 0.05). Markers of liver function, including alanine aminotransferase (ALT), aspartate aminotransferase (AST), and alkaline phosphatase (ALP), did not differ significantly between CON, PL, LDA, and HDA conditions (all p > 0.05). Muscle damage and metabolic markers, including creatine kinase (CK) and lactate dehydrogenase (LDH), also showed no significant changes across treatments (p > 0.05). All measured blood parameters remained within clinically normal reference ranges throughout the study, and no treatment-by-gender interactions were observed (p > 0.05).CONCLUSION: Short-term ashwagandha supplementation did not adversely affect metabolic, lipid, hepatic, or muscle damage markers in resistance-trained adults. These findings suggest that ASH is well tolerated at both low and high doses. However, no clinically meaningful changes in blood biomarkers were observed, indicating that ASH supplementation is safe for short-term use. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.